In scenarios where a Linux system relies on Python for network management, ensuring uninterrupted internet connectivity, even when one network interface goes down, is crucial. This blog post will guide you through using Python and the subprocess module to set up a reliable system capable of seamlessly switching between interfaces.

Python Script for Interface Ping Tests:

import subprocess

def ping_interface(interface, destination_ip):
    try:
        command = f"ping -I {interface} -c 4 {destination_ip}"
        result = subprocess.run(command, shell=True, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
        print(f"Ping result for {interface}:")
        print(result.stdout)
    except subprocess.CalledProcessError as e:
        print(f"Error pinging {destination_ip} over {interface}: {e.stderr}")

# Replace 'eth0' and 'ppp0' with your actual interface names
ping_interface('eth0', '8.8.8.8')
ping_interface('ppp0', '8.8.8.8')
Python
  1. Import the subprocess module for executing shell commands.
  2. Define a function, ping_interface, that takes an interface name and a destination IP address as parameters.
  3. Construct the ping command using the specified interface and destination IP.
  4. Use subprocess.run to execute the command, capturing the result.
  5. Print the ping result or handle any exceptions that may occur.
  6. Replace ‘eth0’ and ‘ppp0’ with your actual interface names and ‘8.8.8.8’ with the IP address you want to ping.

Conclusion

By utilizing Python and the subprocess module, you can easily implement a script to test ping connectivity over different network interfaces. This approach allows you to monitor the status of each interface, facilitating proactive management and ensuring continuous internet connectivity. Incorporate this script into your network management toolkit to enhance the reliability of your Python-based network applications.